Method of protecting the sides and side edges of a metal sheet



Ma n 15, 1955' M. DOWNING 2,704,108

I METHOD OF PROTECTING THE SIDES AND SIDE EDGES OF A METAL SHEET Filed Feb. 8, 1952 IN V EN TOR.

United State "i e METHOD OF PROTECTINGTHESIDES AND SIDE EDGESOF A METAL SHEET Merritt Downing, Pittsburgh, Pa., assignor to American Steel Band Company, Pittsburgh, Pa., a corporation of Pennsylvania Application February 8, 1952, Serial No. 270,582

' adhesive, so in its place synthetic resins often are used.

However, when such an adhesive is employed the felt protective sheets can not be impregnated before they are applied to the metal, because that would prevent the adhesive from drying. In such cases, therefore, it is customary to cement an unimpregnated felt sheet to each side of a metal sheet'by means of a synthetic resin and then, after the resin has dried, the felt sheets are impregnated with asphalt. This works out satisfactorily. as long as the opposite side edges of the metal sheet are not covered, but when they are covered by the felt a new problem is introduced, because each felt sheet which is folded around an edge of the metal sheet overlaps the felt on the other side of the metal. The overlapping portions of the felt sheets are cemented together too, so when the sheets are impregnated with asphalt it can not penetrate the dried adhesive between the overlapping portions of the sheets and therefore does not impregnate the overlapped portion of a felt sheet.

It is among the objects of this invention to provide a method of protecting the sides and side edges of a metal sheet with felt, in which the felt first is cemented in place by a synthetic resin, and in which all of the felt later is impregnated with bituminous material.

In accordance with this invention, a metal sheet is wrapped in felt, by which is meant any protective material that later is to be impregnated with bituminous material. The edge portions of the felt at the side of the sheet overlap. The felt is cemented to the opposite sides of the sheet with a synthetic resin, which also is used to cement the overlapping edge portions together. After the cement has dried, the cemented overlapping portions are provided with a multitude of perforations. Following this, the felt is impregnated with bituminous material which, by reason of the perforations, also impregnates the portion of the felt that is hidden by the overlap.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which Fig. 1 is a plan view of a protected metal sheet made in accordance with my invention, with portions of the article broken away to show underlying layers; Fig. 2 is an enlarged end view of the protected sheet showing the overlapping portions of the protecting felt being perforated between rollers, the thickness of the felt sheets being exaggerated for clearness; Fig. 3 is a plan view of the protected article after it has been perforated; and Fig. 4 is an enlarged fragmentary cross section showing the perforated felt impregnated with bituminous material.

Referring to the drawings, a metal sheet 1, which may be flat, corrugated, or some other shape is wrapped in felt. Although a single sheet of felt may be used, it is preferred to use two sheets 2 and 3, one for each side of the metal sheet. An adhesive cement is applied to the entire area of one side of each felt sheet, and then each one is applied to one side of the metal sheet. The felt sheets are wider than the metal sheet and are applied to it with one side portion projecting beyond an edge of the metal sheet. The felt sheets are so arranged that 7 2,704,108 ,7 g Patented. Mar. 5,1955

one of them projects from one side of the metal sheet, and the other projects from theopposite side of the metal sheet. The laterally projecting portion of each felt sheet then is folded around the adjoining side edge of the metal sheet and over the marginal portion of the felt sheet on the opposite side, whereby to cover and protect the edges of the metal sheet. These felt overlaps 4 are pressed toward the metal sheet so that .they will adhere tothe -underlying felt sheets. The cement 5 that is used for fastening the sheets together is a polymeric material which adheres to metal. Synthetic resins are preferred, most suitably one of the polyvinyl resins because their outstanding combination of properties fits them for this purpose.

After the felt sheets have been applied to the metal sheet, the cement is allowed to dry. Since the felt has not yet been impregnated with asphalt or the like, it does not prevent the volatiles from escaping from the cement. The article then is run between rollers 7 and 8 which engage the overlapping portions of the felt and the opposite sides of the unit, as shown in Fig. 2. The rollers 7 that engage the overlapping portions 4 of the felt sheets are provided with closely spaced annular rows of teeth 9 or perforators, which cut holes or slits 10 (Fig. 3) through both layers of the felt sheets and the intermediate layer of impervious cement, substantially down to the metal.

The article with its perforated sheets then is impregnated with a suitable bituminous material, such as asphalt. Due to the perforations 10, the impregnant can penetrate the cement layer between the overlapping portions of the felt sheets and impregnate the felt layer next to the metal. Consequently, the entire area of each felt sheet is impregnated with the bituminous material. Of course, the impregnant 11 also fills the perforations so that no holes are left for collecting moisture.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. The method of protecting the sides and side edges of a metal sheet, comprising wrapping the sheet in felt, overlapping edge portions of the felt at the side of the sheet, cementing the felt to the opposite sides of the sheet, cementing said overlapping edge portions together with a cement that will form an impervious layer when dry, allowing the cement to dry, then providing the cemented overlapping portions and the cement between them with a multitude of perforations, and impregnating the felt with bituminous material some of which passes through the perforations in the perforated cement to impregnate the overlapped portion of the felt next to the metal sheet.

2. The method of protecting a metal sheet, comprising placing sheets of felt against opposite sides of the metal sheet, folding at least one of the felt sheets around the side edges of the metal sheet and into overlapping relation with the other felt sheet, cementing the felt sheets to the metal sheet and to each other with a cement that will form an impervious layer when dry, allowing the cement to dry, then providing the cemented overlapping portions of the felt sheets and the cement between them with a multitude of perforations, and impregnating the felt sheets with bituminous material some of which passes through the perforations in the perforated cement to impregnate the overlapped felt sheet portions next to the metal sheet.

3. The method of protecting a metal sheet, comprising placing sheets of felt against opposite sides of the metal sheet, folding one side of one felt sheet around one side edge of the metal sheet and folding the opposite side of the other felt sheet around the other side edge of the metal sheet with the folded portion of each felt sheet overlapping an edge portion of the other felt sheet, cementing the felt sheets to the metal sheet and to each other with a cement that will form an impervious layer when dry,- allowing the cement to dry,

then providing thecementedioverlapping portions of the felt sheets and the cement between them with a multitude of perforations, and impregnating the felt sheets with bituminous material some of which passes through the" perforations in the perforated cement to impregnate tlfie overlapped felt sheet portions next to the metal s eet.

References Cited in the file of this patent UNITED STATES PATENTS 1,096,579 Wa1jdell May 12, 1914 Lyijyne'n Jan. 1, 

